This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A056027 #26 Feb 18 2025 04:05:48
%S A056027 1,38,40,65,75,110,131,134,155,158,179,214,224,249,251,288,290,327,
%T A056027 329,354,364,399,420,423,444,447,468,503,513,538,540,577,579,616,618,
%U A056027 643,653,688,709,712,733,736,757,792,802,827,829,866,868,905,907,932,942
%N A056027 Numbers k such that k^16 == 1 (mod 17^2).
%H A056027 Amiram Eldar, <a href="/A056027/b056027.txt">Table of n, a(n) for n = 1..10000</a>
%H A056027 <a href="/index/Rec#order_17">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-1).
%F A056027 From _Mike Sheppard_, Feb 17 2025: (Start)
%F A056027 a(n) = a(n-1) + a(n-16) - a(n-17).
%F A056027 a(n) ~ (17^2/16) * n.
%F A056027 G.f.: (x*(1 + 37*x + 2*x^2 + 25*x^3 + 10*x^4 + 35*x^5 + 21*x^6 + 3*x^7 + 21*x^8 + 3*x^9 + 21*x^10 + 35*x^11 + 10*x^12 + 25*x^13 + 2*x^14 + 37*x^15 + x^16))/((1-x)*(1-x^16)).
%F A056027 (End)
%t A056027 x=17; Select[ Range[ 1000 ], PowerMod[ #, x-1, x^2 ]==1& ]
%t A056027 (* or *)
%t A056027 LinearRecurrence[{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -1}, {1, 38, 40, 65, 75, 110, 131, 134, 155, 158, 179, 214, 224, 249, 251, 288, 290}, 55] (* _Mike Sheppard_, Feb 17 2025 *)
%Y A056027 Cf. A056021, A056022, A056024, A056025, A056026, A056028, A056031, A056034, A056035.
%K A056027 nonn,easy
%O A056027 1,2
%A A056027 _Robert G. Wilson v_, Jun 08 2000